This invention relates to a boot process for a computer, to a boot ROM and to a computer having a boot ROM.
In particular, although not exclusively, the invention relates broadly to a remote boot process whereby a computer may be initialised—i.e. booted—using boot program information (known as a boot image) obtained from a remote source, i.e. a source in communication with—but separate from—the computer concerned.
Remote boot processes are useful for a variety of reasons. First of all, if a particular client machine fails to boot as a result of a hardware or software malfunction, a remote boot image can be downloaded from another location to provide the malfunctioning client machine with a replacement code which enables, for example, remote problem notification, diagnosis and possible resolution of the problem.
In addition, remote boot processes allow networks to be composed of a number of “thin client” machines having little or no local data storage capability, with the required operating system, for example, being downloaded from a remote data store as and when the machines are initiated. This reduces the cost of the network clients and provides a persistent image that can be restored easily and that cannot be damaged by a local user.
A common remote boot system is Intel's Wired for Management (WfM) standard which incorporates a pre-boot execution environment (PXE) protocol.
In brief, the PXE protocol requires an appropriately configured BIOS and boot ROM which, when the computer is powered up, are effective to broadcast a general DISCOVER signal which is intended eventually to reach a local Intranet DHCP (Dynamic Host Configuration Protocol) server which, in turn, provides the client machine with a list of appropriate available boot servers. Using a low level protocol such as TFTP, the client machine then downloads the required boot image from an appropriate boot server and executes the boot image in generally conventional fashion.
The PXE approach, whilst operating satisfactorily in an enclosed (Intranet) environment does however have some disadvantages. First of all, a specific DHCP server is required—this is not only expensive but can require local maintenance. In addition, such servers must be configured to perform PXE-specific tasks, thus necessitating the presence of a “PXE-ready” infrastructure. Thirdly, and perhaps most importantly, the protocol used by the PXE approach is severely limiting, in that it is unable to send or transmit signals beyond the enclosed Intranet.
It is an object of the present invention to provide a boot process for a computer which overcomes or at least alleviates these problems, and to provide a boot ROM which allows a computer to operate in such an improved manner. It is also an object of the present invention to provide a computer having such a boot ROM.